using System;

public static class TimeSpanExtensions

    {

        public static TimeSpan AddMinutes(this TimeSpan span, int minutes)

        {

            return minutes < 0 ? span.Subtract(TimeSpan.FromMinutes(minutes)) : span.Add(TimeSpan.FromMinutes(minutes));

        }

​

        public static TimeSpan AddHours(this TimeSpan span, int hours)

        {

            return hours < 0 ? span.Subtract(TimeSpan.FromMinutes(hours)) : span.Add(TimeSpan.FromMinutes(hours));

        }

    }

​

public class Program

{

    public static void Main()

    {

        var ts =  TimeSpan.FromHours(1);

        Console.WriteLine(ts);

        ts = ts.AddMinutes(5);

        Console.WriteLine(ts);

        ts = ts.AddMinutes(-5);

        Console.WriteLine(ts);

    }

}